Information transfer systems



Feb. 2, 1965 M. E. cLYNEs INFORMATION TRANSFER SYSTEMS 4 Sheets-Sheet l Filed July 27, 1959 Feb. 2, 1965 M. E. cLYNEs INFORMATION TRANSFER SYSTEMS Filed July 27, 1959 4 Sheets-Sheet 2 JNVENTOR. MANFRED E. cLYNEs ATTORNEY Feb. 2, 1965 M. E'. cLYNEs TNRoRNATToN TRANSFER sTsTEMs 4 Sheets-Sheet 3 Filed July 27, 1959 JNVENTOR.

MANFRED E. cLYNEs BY ai; Mr

ATTORNEY 4 Sheets-Sheet 4 Filed July 27, 1959 FROM PULSEl SHAPER 2I4 FROM -IPULSE SHAPER 2|4 TO LINE 2|3 INVENTOR.

MANFRED E. CLYNES ATTORNEY 3,168,721 l INFORMATION TRANSFER SYSTEMS Manfred E. Clynes, Orangeburg, N.Y., assignor, by mesne assignments, to Technical Measurement Corporation, v North Haven, Conn., a corporation of Delaware Filed July 27, 1959, Ser. No. 829,694 17 Claims. (Cl. 340-167) include magnetic tape recorders, do not readily lend themselves to transferring such signals. Magnetic recording systems require a time rate of change of magnetization -to-produce a signal during reproduction. Therefore, if

the recorded signal is constant, there is no rate of change of magnetization and consequently, no signal can be reproduced. Due to this phenomenon, conventional maguetic tape recorders, although they can reproduce signals having frequencies in the kilocycle range, are unable to reproduce signals having frequencies much lower than thirty cycles.

To reproduce signals down into the D.C. range, complicatedsystems have been suggested. One system employs modulation techniques. In particular, a high frequency carrier signal is frequency modulated by the signal representing the'information. To insure good linearity, it is necessary that the frequency deviation be keptto less than about 8%. Consequently, to provide a substantially noise free system, highly accurate, wow-free tape transport mechanism are mandatory. Also, elaborate filtering is required in the electronic circuits to obtain a truly ,linear D.C. response from the sinusoidally varying carrier signal. Such filteringcircuits are extremely complex and vrequire modification when the playback speed is changed.

It is'accordingly a general object of one embodiment ,United States Patent O of the invention, to provide an improved information transfer system. Another object of this embodiment of the invention is to provide an information transfer system wherein the output waveforms are either proportional to or identical with, the input waveforms.

A further object of said embodiment of the invention is to provide an improved Vinformation transfer system which can handle information in the form of signals having frequenciesextending through the low frequency range to the D.C. extreme,

Yet another object of said embodiment of the invention is to provide an improved information transfer system for handling signals that extend to the D.C. extreme, which may be used with conventional, simple magnetic tape recorders.V

Briey, in accordance with said embodiment of the invention, the system includes pulse generating means which generates pulses having a repetition rate related to-the Aamplitude of the signals representing the information. The pulse generating means feeds a pulse shaping means which standardizes the shape and amplitude of the pulses In further embodiments of the invention, first and second signal sources respectively transmit signals to iirst and second pulse generating means which generate pulses of substantially constant duration and having repetition rates related to the amplitudes of the signals received from the respective signal sources. A first pulse shaping means receives the pulses from the rst pulse generatingmeans 'and transmits the received pulses as pulses of a iirst polarity with a standard duration and amplitude. Similarly, the second pulse shaping means transmits pulses of a second polarity with a different standard duration and amplitude. A mixing means mixes the pulses from the two pulse shaping means to permit their transmission over a single channel to a utilization means such as a magnetic tape recorder.

With such-a tape recorder, the reproduction section thereof feeds first and second signal separation means. The first separation means only transmits the iirst polarity signals and the second separation means only transmits the second polarity signals. The separated signals are then selectively fed to the iirst and second pulse shaping means for standardization. The standardized pulses are respectively fed to iirst and second utilization means which convert them to signals having amplitudes related to the pulse repetitionrates of the pulses received from the tape recorder via the first and second pulse shaping means.

Other objects of this invention will in part be obvious l.and in part hereinafter pointed out.

In the drawing,

FIG. 1 is aschematic diagram of an information transfer system in accordance with one embodiment of the invention;

FIG. 2 is av block diagram of an alternate embodiment of the invention wherein two different kindsy of information represented by signals are transferred over a single channel;

FIG. 3 is a block diagram of an alternate embodiment of the system shown in FIG. 2, wherein the single channel ,is a magnetic tape recorder; L n l FIG. 4 is a schematic diagram of afmixerthat may be used in the system of FIG. 2 or 3; and FIG. 5 is a representation of-waveforms for signals received and transmitted by the mixer of FIG. 4.

Referring to FIG. 1, anV information transfer system is shown comprising a signal source 10, pulse generating means or pulserfrequency modulatorr 12, pulse shaping means 14, utilization means yor -iilter 16 and a tape recorder 18, which is preferably of the magnetic type having recording and reproducing sections. Information represented by signals having different amplitudes is transmitted via switchr20` to pulse frequency modulator 12. Modulator 12, hereinafter more fully described, transmits pulsesof substantially constant duration but having a repetition rate which is-related to the amplitude of the received signals. 1 f

The pulses from modulator 12 are selectively fed, via

switch 22 topulse Shaper 14. Pulse shaper 14, hereinafter more fully described, transmits a pulse of standardA amplitude, shape and duration, for each pulse it receives. The received pulses can'be considerably misshapen, yet pulse shaper 14 will transmit standard pulses. The standardized pulses will have the repetition rate of the received pulses. The standardized pulses areV fed to filter 16 and via line- 24 to the recording section of tape recorder 18. Recorder 18 may be of the conventional single or multispeed, magnetic tape type.

Tape recorder 18 has a recording section for recording received pulses on a channel Vof magnetic tape, and a reproducingsection for playing back at a later time, the pulses recorded on the magnetic tape. The reproduction section is coupled via the '1ine`26 to switch 22 for selective connection to pulse Shaper 14. Filter 16, hereinafter more fully described, is a means for generating signals having amplitudes related to the repetition rate of the standardized pulses transmitted by pulse shaper 14.

During operation, signal source transmits signals `which may varyin amplitude at an exceedingly slow rate, or Vmay transmit'direct current signals of different amplitudes. These signals control the repetition rate of the pulses` generated by pulse frequency modulator 12; Thus, the Vgreater the amplitude of thereceived signals, the `greater the repetition rate of the generated pulses. With movable switch contact 22A in engagement with fixed switch contact 22B, the pulses from modulator 12 are received by pulse shaper 14 for standardization. It is noted that the standardized pulses have the same repetition ratev as the received pulses. The standardized pulses are fed to the recording section of tape recorderl. Such be monitored.

When it is desired to playback the pulses recorded on the magnetic tape of recorder 1S, the movable switch contact 22A is engaged with lixed switch contact 22C and the playback mechanism of recorder 18 is activated.' The reproduced pulses are `fed via .line 26and switch22 to Y pulse shaper 14.Y It is noted that although these playback pulses may have lost some of their shape, they can Astill trigger the pulseshaper'14 which transmits a standare different, the pulses will beidentical except for the repetition rate. It is noted that even in this case, the standardized reproduced pulses will have -the same duration as the originallyl standardized recorded pulses. v

fInV any event,=the standardized reproduced pulses are lfed to filter 16, where they are converted to signals having Vamplitudes related` to their repetition ratesf These signals may'be'usedto energize devices suchas a conventional pen recorder, oscilloscope or other visu'alr'ecording device. i More particularly,pulsetrequency modulator 1i?.` is an astable asymmetrical multivibrator having about a 15% duty cycle, and comprises transistors 28, 30. Transistor emitter 285A is connected to ground while base '28B isV connected vial resistor 32 to iixed switch contact 20B, via resistor 34 to fixed switch contact 20C and via resistor 38 to a potential source B-; and collector 28Czis coupled via resistor 36 to said potential source.

' Transistor emitter 30A is groundedwhile base coupled via resistor 40 to potential source 13.-; and' collector 36C iscoupled via resistor .42` to s'aidnpotential source. Capacitors 44, 46 respectively couple transistor collector 28C torbase 30B and transistor collector 30C to 30B Ais A train from pulse Shaper -14to a signal having an an`1. l Vplitude related to therepetition rate of the train of pulses.

base 28B. klt is noted that the potential onr base 28B I ,"deterrnines the free running period of the astable multivibrator. AThis potential is controlled by the signals 4fed from signal source 1Q via the resistors 32 or 34. Furthermore, the control is only related tothe `duration ofthe state of duration is substantially constant. Y

It is noted that to obtain optimum frequency response for' a recording speed, it is desirable Vto choose the basic i pulse repetition rate in accordance with the recording speed. This'may `be accomplished by changing thermagnitude of capacitors 44, 46 in a fixed ratio. Resistor 38,

ythe ratio of capacitors 44, 46, and the ratio of resistors 36, 4t) determines the basic or no signal input duty cycle. frCap'acitor 47 couples collector' SGC to fixed switch contact 22B, -whichvis' also coupled to ground via resistor 48. Pulse Shaper 14Y comprises the trigger circuit 49and the monostable multivibrator 5,0.,

Trigger circuit 49, which is a conventionallSchmitt trigger, hasjthe, property of vrassuminga first stable state 4 i when the potential at its input exceeds a first value, and of assuming a second stable state when the' input potential is of a smaller amplitude. The transistion between these stable states is extremely sharp and precise. Monostable multivibrator 50, of conventional type, has the property of resting in a stable state until triggered. On triggering it transmits a pulse Vof predetermined Aduration and amplitude. Y

More particularly,trigger circuit 49 includes-transistors 52, 54. Collector 52C of transistorv 52'is coupled via resistor 56 to potential source B- while its base 52B is connected to movable switch contact 22A. Collector 54C of transistor 54 is connected via resistor 58 to ,poten-V tial source B-. Base 54Bof transistor 54isconnected via lead'60 to-transistor collector 54C. The emitters 52A and 54A are coupled via common resistor 61 `to ground. The coupling network comprises capacitor 62 and resistor 64, which couples trigger circuit 49 to monostable vibrator 50.

Monostable multivibrator 50 comprises transistors 66, V68. The collector `66C of transistor 66 is coupled viare-` sis'tor '70 to potential source, B- while the emitter 66A is connected'to ground. Similarly, collector 68C of transistor' is coupled via resistor 72 to potential source .B-, while emitter 63A is Vconnected to ground potential.

-Resistor 74`couples collector 68C to base 66B, which receives trigger pulses via capacitor 62. Capacitor 76 couples collector .65C to base 63B. Movable contact 78A of switch 78 is also coupled .to base 6tll?`. The fixed contacts 7SB, 78C and '78D are respectively coupled via resistors 79, 80 and 81 to potential source B-. y Y

Capacitor 76 and resistorsg79, 80, S1 formthe timing network Yfor monostable multivibrator 50. VSaid-resistors Vpermit a change of pulse `durationV in. accordance with Ydiiierent playback speeds so that the sameduty cycle is maintained with possible overlap of playbackpulses at faster playback speeds. Ernitter 68C',`which is the output of pulse shaper 14,'is coupled via'line 24, to tape recorder 18 and to iilter 16.*

Filter 16 comprises a plurality of llilter sections which couple pulse Shaper 14 to an emitterfollower amplifier. f

Such a combination is capable Yof'converting thepulse In particular, lter 16 includes the serially disposed resistors S2, 84, 86, with one Vend of resistor S2 connected to `trai'nsistor collector 68C. The movable contact'SSA of switch .88V is coupled to the junction of Vresistors 82,

84; movable contact 99A of switchgtlis coupledfto the junctioniofresistors 84, '867 and movable contact 92A of switch 92` is coupled Vto the free end of resistor 86.

Capacitor 94 couples fixed rswitch contact 88B to ground and capacitor/96 couples the' other'xed switch contactsy 88C, 88D to ground. Similarly, capacitors 98T, respectively couple fixed Vswitch contact 90B and Vfixed switch contacts 99C,`90D, to ground. Also, capacitors v192, 104 respectively couple fixed switch contact 92B and xed'switch contacts 92C, 92D,V to ground.

Emitterrollower amplifier 195, which is responsive to the above? .descril'fed` 'filter network, Y- comprises transistor .106 whose collector 106C is Yconnected to potential source B whose baise' 166B is connected toresistor 86 vand whose emitter 106Aisfcoupled` via the serially disposed `resistor 108 andl thyrite 1,10 to ground. The output of Y filter`16 isthe juncture of resistorltland thyrite 110.

It Will be recalled thatthe pulse train fed to filter 16 comprises pulses of constant duration and amplitude with a repetition rate that varies. ln etfect,-the Vdutycycle v aries and accordingly, the average component 0f voltage similarly varies. The lrole of the resistance-capacitance stages in filter 16 istopassthis average component Vof voltage.- and to :lilterout the varying components. ofthe voltage. "f Thyrite V110 in the emitter circuit of the emitter fol'- lower amplifier: 105 further linearizesthe output .signal since pulse repetition rate changes are not precisely linear with changes of input signal.V Furthermore, there may be vary slight changes in the amplitude and width of the pulses from the monostable multivibrator 50 with changes in the pulse repetition rate.

The -movable switch contacts of switches 22, 78, 88, 90 `and 92 are ganged together so that the proper time constants are provided for each operation of the device. When the switches are in the recording position, the movable contacts engage the B fixed contacts of the respective switches, to cause the pulse Shaper 14 to receive signals from modulator 12; the multivibrator 50 generates pulses of proper width; and the appropriate filter capacitors are switched into filter 16.

Similarly, when the movable contacts engage the C fixed contacts of the respective switches, pulse Shaper 14 is coupled to tape recorder 18, the required resistor is coupled into the timing circuit of multivibrator 50 and the appropriate capacitors are connected into filter 16. If playback is to be at four times recording speed, Athen the movable contacts Yengage the D fixed contacts of the respective switches and the time constant of the multivibrator 50 is quartered.

By combining elements similary to those of FIG. l, it is possible to provide an information transfer system which receives signals from two sources, combines pulses representing theseV signals, transfers the pulses over a single transmission channel, andv separates the pulses at the other end of the channel Where they are reconverted to signals before transfer to utilization devices.

Such a system is shown in FIG. 2, where elements corresponding to elements indicated in FIG. 1, have reference numbers increased by 200, and only the differences will be described. Signal sources 210,210' trans- Imit signals having amplitudes related to the information to be transferred. The information is in general, different for each signal source. vPulse frequency modulators 212, 212 are similar to modulator 12 except that the time of duration of. the pulsesV generated by modulator 212 is N times longer.

Pulse Shapers 214, 214' receive the pulses and transmit standardized pulses in the manner described in connection with pulse Shaper 14, except that the amplitude of the standardized pulses from pulse Shaper 214 have l/Nth lthe amplitude of the pulses from pulse Shaper '14 and the pulses transmitted by .pulse Shaper-214' have an opposite polarity, see the waveforms A,"B. of FIG. 5. The inverted -waveforms are Vreadily obtainable by Vtaking the output from collector 66C, instead of collector 68C in multivibrator 50 of FIG. 1.

In any event, the standardized pulses are combined in mixer 21S, which is shown in detail in FIG; 4, as a conventional combining circuit, to produce the Waveform C of FIG. 5. It is noted that because of the relative amplitudes and durations of the mixed standardized pulses are different, there is 'no chance of mutual cancellation when pulses of opposite polarity coincide. 'f

Mixer 215 feed line 213, `which may be any standard communications link. Rectifiers 217, 217 receive the mixed standardized pulses.V Said rectifiers, which may be ofconventional diode type, are oppositely polarized to permit separation of the positive and negative pulses.v

Positive pulses are fed to amplifier 219 for amplification while the negative pulses are fed to amplifier 219' for amplification and inversion. It is noted that the gain of amplifier 219 is approximately N times the'gain of amplifier 219'. Amplifiers 219, 219' respectively feed pulse Shapers 212A, 212A'. Pulseshapers 212A, '212A' are identical with pulse Shapers 212, 212' respectively. Thus, the pulses transmitted by Shapers 212A, 212A'v are identicalV to the pulses transmitted by Shapers 212, 212';

Filters 216, 216', which are the same as filter 16 of FIG.'` 1, respectively receive the pulses transmitted by Shapers 212A, 212A' and convert these pulses to signals having amplitudes related to the respective pulse repeis similar to recorder 18.

repetition rates of the pulses.

tition rates. The signals are transmitted-by filters 216, 216 respectively to utilization means 221, 221A', which may be conventional pen recorders.

Although the information transfer system is shown with a communications link, it may also be used with a magnetic storage device such as a tape recorder which serves as Vstorage means for the information before it is transmitted 'to utilization devices. Such a system is shown in FIG.

3 which includes elements similar to those employed in FIGS. 1, 2. Accordingly, similar'elements will be given 'reference numerals increased by 300 and only the differences will be pointed out. l

Signal Vsources 310, 310' respectively transmit to pulse frequency modulators 312, 312', signals having amplitudes related to the information be transferred. The information is usually different for each signalv source. Pulse frequency modulators 312, 312' are similar to modulators 212, 212' and accordingly generate trainsof pulses having fixed but different time durations with lrepetition rates related to the respective signals received from signal sources 310, 310'.

The train of pulses generated by modulator 312 is transmitted to fixed contact 322B of switch 322 while the train of pulses from modulator 312' is transmitted to fixed contact 322B' of switch 322'. During a recording operation, movable contacts 322A, 322A' are respectively connected to fixed contacts 322B, 322B', and accordingly, pulse Shaper 314 receives pulses frommodulator 312,

while pulse Shaper 314' receives pulses from fmodulator 312'. i

Pulse Shapers 314, 314', which are similar to pulse vShapers 214,' 214', transmit standardized pulses to mixer 315 and also to filters 316, 316'. Filters 316, 316', which are similar to filter 216, 216', may be coupled to utilization devices to permit monitoring of the pulses being recorded. Mixer 315, which is similar to mixer215, combines the-pulse trains and transmits the combined pulse trains to the'recording section of tape recorder 318, which On playback, the reproduction sectionV oftape recorder l318 transmits the combined pulse train to'rectifier's 31,7-,

317'which are similar to rectifiers 217, 217'. Rectifiers 317, 317' separate the pulses according to polarity and transmit trains/ofY Separated pulses respectively to ampliners 319, 319"wh ich are similar to ampners 219, 219'.

-form the above described functions of converting-the pulsetrains-to signalshaving amplitudes related to the It is noted that by employing the systemvof the instant invention, it is possible to v'have recording to playback speed ratios whichv are greater than, less than, or equal to one.

It is further noted that although the recording system of FIG. 3 has been'described fora single'channel tape recorder,.itV is possible to employfsuch a system for each channel of a multichannel taperec'order and therefore double the amount of information' stored. i There are thus been described improved information transfer means which can transmit information represented by signals having frequencies extending idown to and including the D.C. extreme.` Such means is ideally suited for incorporation with magnetic tape recorders which have low frequency responses of only about thirty cycles. The use of the invention in such tape recorders minimizes the effect of wow and flutter since the signals may be modulated over wide limits without loss of linearity. Such wide range modulation is possible because the filtering of the signals does notfrequire conventional tuned track.

- Representative valuesv of elements of the system described herein, include: resistor 32, 100,000 ohms; resistor 34, 10,000 ohms; resistor 36, 2,200 ohms; resistor 38, 68,000 ohms; resistor 40, 47,000 ohms; resistorV 42, 1000 ohms; capacitor 44, .005 mfd,; capacitor`46, .04

mid.; capacitor 47, .O03 mid.; resistor 49, 10,000 ohms; vresistor 56, 2,200 ohms; resistor 58, 17,000 ohms; -res-is- '82, 10,000 ohms; resistor 84, 39,000 ohms; resistor 86,

120,000 ohms; capacitor 94, .100 mid.; capacitor 9,6, .250 mfd.; capacitor 98, .030 mfd.; capacitor 100, ,008 mfd.; capacitor 102, .010 mfd.; capacitor 104, .0025 mfd.; re-

sistor 108, 6,800 ohms; transistors V28, 30-'CK722; 'transistors 52, 54-2N217; transistors 6663--2N269; and transistor 106'-CK722. `Thyrite Y110, a non-linearresistor-G E; 21/839G1. 1- j Y f As various changes might be made vin the'embodiments of the inventionherein shownrand described, Without departing from the spirit thereoffit is understood thatl all matter herein shown or described shall be deemed'illustrative and not by way of limitation except as set forth in the appended claims. "7 l, fe f Having thus disclosed myinvention', I `claim -as AYnew and Adesire to protect by LettersV Patent:l Y

1'. A transfer system lfor information represented by'an .input signal of varying amplitude comprising: a'variable repetition rate pulse generatingY means; said generating means being modulated by Ysaid input signal to` generate ,inputpulses 'havingra repetition rate which varies a's a function of the amplitude of `said Yinput signal,"m'eans triggered by' saidinput pulses to producea iirst 'train of standardized pulses of constant'duration andV amplitude and'havingja repetition rate correspondingY to that' of Vsaid,

Vinput pulses, means'tovconvey-'said irsttrain of standardized.` pulses through'a mediumwhich 'distorts' said ,standardized pulses, means'todetect said conveyed pulses to Vprovide incoming pulses, meanstriggered by said in.- comin'g pulses to producea second' train of standardized pulses of constant amplitude and duration and having a repetitionrate corresponding Vto that'of said incoming pulses, and means toY average said second train of Ystandardized pulses to develop an output signalwhoseamplitude varies as a function of the repetition ratefof the pulses in said second train. 1 j, Y f

' f2. A transfer' system, as set forthV in claim 1,-Wherei'n said means responsive to'sa'id 'input signaltof'produce g input pulses is constituted by an asymmetricallmultivibraitor. Y Y

-3. 'Atransfersysterm as setforthk in claim l, ywherein said means to produce 'said tirst and ysecond v'trains of standardized pulses comprises a trigger vcircuitV responsive tothe/applied pulses, and Va monostable pulse generator coupledto said triggerfcircuit to-produce in response to each triggerpulse aesingle standardized pulse. a

4. A transfer,system,v as'setvforthainclaim l, wherein said means to average "said, second trainof standardized pulses' comprises a passive resistance-capacitance lilter network. Y v' j" Y 5. A transfer system-for information represented by aninput signal ot varying-amplitude comprising: means responsive to said input signalY to"generate`input pulses having a repetition rate'which varies as a function ofthe amplitude of said input signal, means'triggered bysaid input pulses to produce a rst'trainof standardized pulses of; constant duration v'and amplitude andhaving a 'repetitionrate corresponding Vto'that of said 'input pulses, means -to record 'said rst train of standardized pulses, means to reproduce said recordedrpuls'es toe provide :play-back pulses, 'means ltriggered by said play-back pulses to `pro- .velop' an output signal whose amplitudevariesy as afunction of the` repetition rate of ,the pulses' in said second train. i

6. A transfer system, as set forth in claim 5, wherein rsaid means to record and to reproduce pulses is constituted by a magnetic tape system having a recording and play-back section. i t

7. A transfer Asystem for Yinformation represented by an input signal of varying amplitude comprising: a pulse generator responsive to saidY input signal to .produce input pulses having a repetition rate which varies as a function of the amplitude as' said signal, a pulse shaper constituted by a triggercircuit and a multivibrator coupled thereto to produce standardized pulses of constant duration and amplitude with a repetition rate which corresponds to that of the pulses applied to said trigger circuit, a pulse storage system coupled to said standardized pulses having a recording section and a reproducing section, a passive network to 'average pulses appliedY thereto toproduce an output signal whose amplitude varies as a function ofthe repetition rate Yof .the pulses applied thereto, and` selective switching means` Vhaving a recordingposition in which said input pulses are appliedto said Vpulse shaper'to produce Va tirst'train of standardized pulses which are fed to the recording section of said storage system and having a reproducing positionV in which playback pulses derived from s aid reproducing section' are applied 'to said pulse `shaper to produceV a second train of standardized pulses which arefed to said passive network to produce an output signal.

8. yA transfer systemffor information represented by an input signalV of varying :amplitude comprising: an asymmetrical pulse generator responsiveV .to said 'input signal' to?. produce input pulses having a repetition rate which isY proportional to Vthe amplitude ofA saidsignal, a pulse Shaper constituted-by aY Schmitt trigger circuit and a. monostable multivibrator coupled thereto toproduce standardized pulses ofL constant duration 4and amplitude with arepetition rate cor-responding to that ofthe pulses applied-to said trigger circuit,1a.magnetic recording systemhaving a` recording section connected to receive said standardized pulses anda play-backsectio-n, apass'ive resistance-capacitance network to average pulses applied thereto, and selective switching means having a recording shaper'to produce a second" train of standardized pulses` vwhich are fed to said' network to produce an output signal whose amplitude varies in `'proportion to the repetition rate of said second train of pulses.

9. "An information conversion system for recording and reproducing varying signals comprising a source of signals having amplitudes,representativeof the'information being transferred, an astab-leasymmetrical multivibrator for generating pulses having substantially cons-trant durations anda pulse repetition rate related tothe amplitudes of the signals received from said sign-al source, a .triggercircuit 'responsivefto said astable asymmetrical multivibrator, said trigger circuit being activated when each received pulse Vexceeds a predetermined amplitude to generate a pulseof substantially constant amplitude for each-pulse received, a monostable multivibratorresponsive .tosaid trigger circuit Vfor generating' p-ulsesfjsubf stantially constant amplitudeV and duration, a` magnetic tape storageV system having; recording and reproducing sections, said recording section rbeing responsive to said monostable multivibrator for recording said pulses, means coupling said trigger circuit to said tape reproducing section, and reconversion means responsive 'to said monostable multivibrator for generating signals having amplitudes related to the repetition rate of the pulses generated \by said monostable multivibrator.

l0. The system of claim 9 wherein said reconversion means includes a li'ilter and an emitter follower amplifier responsive to said iilter, said emitter follower ampliiier including a .thyrite in the emitter circuit.

11. An information transfer system comprising first and second signal sources having variable amplitudes representing the infomation being transferred, first and second pulse generating means respectively responsive to said signal sources, said iirst and second pulse generating means generating pulses of substantially cons-tant duration and ypulse repetition rates representative of the amplitudes of the signals from said signal sources, tirst and second pulse shaping means respectively responsive to said first and second pulse generating means, said first pulse shaping means transmitting pulses of one polarity having a substantially constant amplitude and duration with a repetition rate equal to .the repetition of received pulses, said second pulse shaping means transmitting pulses of opposite polarity having substantially constant amplitude and duration with a repetition rate equal to the repetition rate of received pulses, mixing means combining the signals from said iirst yand second pulse shaping means, and a transmission link for transmitting a combined train of pulses from said Imixing means, magnetic storage means having a recording section coupled to said transmission link and responsive .to the output from said mixing means, and a reproducing section, said reproducing section having a single readout channel rfor the comtained recorded signals, iirst and second signal separating means responsive to said single lreadout: channel, said rst follower amplilier responsive to said lfilter, and a t'hyrite signal separating means transmitting yreproduced pulses of said yone polarity, said second signal separating means transmitting reproduced pulses of said opposite polarity, means for causing said rst pulse shaping means to be selectively responsive to said -irst signal separating means, means for causing said second pulse shaping means to 'oe selectively responsive -to said second signal separating means, and iirst and second signal utilization means respcctively responsive to said tirst and second pulse shaping means yfor respectively converting the pulses from said first `and second pulse shaping means to signals having amplitude related 'to `the repetition rates of received pulses.

in the emitter circuit of said amplitier.

13. The system of claim 11 wherein said first and second signal separating means include a rectilier, the recti-iers of said lirst and second signal separating means being oppositely polarized.

14. The system of claim l1 wherein the amplitude of the pulses transmitted by said rst pulse shaping means is N times the amplitude of the pulses transmitted by said second pulse shaping means.

15. The system of claim 11 wherein the duration of the pulses Itransmitted =by said second pulse shaping means is N times the duration .of the pulses transmitted by said first pulse shaping means.

16. The system of claim 11 wherein the amplitude of the pulses transmitted from said lirst pulse shaping means is N times the amplitude of the pulses transmitted from said second pulse shaping means, while the duration of the pulses from said second pulse shaping mean-s is N times the duration ofthe pulses from said first pulse shaping means.

17. The system of claim 16 wherein said second signal separating means includes amplifying means lfor amplifying of pulses separa-ted yby said second signal separating means.

References Cited by the Examiner UNITED STATES PATENTS 2,418,268 4/47 Lawson 332-14 2,551,771 5/51 Spielman 328-58 X 2,574,207 11i/5l Christian 332-14 2,587,541 2/52 Shenlc A 332-16 2,592,572 y4/52 Jennings 179-156 X 2,632,847y 3/53 Reed 328-57, 2,653,237 9/53 Johnstoneet al. 328-58 2,803,809 8/57 Tilley 340-15 2,839,727 6/58 LoZier 179-15.6 2,883,650 4/59 Brockway 340-167 X 2,924,788 2/60 Maurushat Y 332-14 2,942,112 6/60 Hearn 340-18 2,991,415y 7/61 Pierson 328-140 X NE1L C. READ, Primary Examiner.

Examiners. 

1. A TRANSFER SYSTEM FOR INFORMATION REPRESENTED BY AN INPUT SIGNAL OF VARYING AMPLITUDE COMPRISING: A VARIABLE REPETITION RATE PULSE GENERATING MEANS, SAID GENERATING MEANS BEING MODULATED BY SAID INPUT SIGNAL TO GENERATE INPUT PULSES HAVING A REPETITION RATE WHICH VARIES AS A FUNCTION OF THE AMPLITUDE OF SAID INPUT SIGNAL, MEANS TRIGGERED BY SAID INPUT PULSES TO PRODUCE A FIRST TRAIN OF STANDARDIZED PULSES OF CONSTANT DURATION AND AMPLITUDE AND HAVING A REPETITION RATE CORRESPONDING TO THAT OF SAID INPUT PULSES, MEANS TO CONVEY SAID FIRST TRAIN OF STANDARDIZED PULSES THROUGH A MEDIUM WHICH DISTORTS SAID STANDARDIZED PULSES, MEANS TO DETECT SAID CONVEYED PULSES TO PROVIDE INCOMING PULSES, MEANS TRIGGERED BY SAID INCOMING PULSES TO PRODUCE A SECOND TRAIN OF STANDARDIZED PULSES OF CONSTANT AMPLITUDE AND DURATION AND HAVING A REPETITION RATE CORRESPONDING TO THAT OF SAID INCOMING PULSES, AND MEANS TO AVERAGE SAID SECOND TRAIN OF STANDARDIZED PULSES TO DEVELOP AN OUTPUT SIGNAL WHOSE AMPLIPULSES IN SAID SECOND TRAIN. 